Reaktion #465717

Reaktionsgleichung

2,5-bis(p-toluidino)terephthalic acid

water

→

2,9-dimethylquinacridone

Ausbeute 83.9%

Lösungsmittel

methanol

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe stirred mixture was irradiated in the microwave oven for 2.0 minutes, during which time the temperature
2. 2
   Sonstigerose to 230° C
3. 3
   TemperaturThe reaction mixture was cooled to 150° C.
4. 4
   Temperaturat reflux for one hour
5. 5
   Temperaturcooled to 60° C.
6. 6
   Temperaturheated at 60° C. for 30 minutes
7. 7
   FiltrationThe solid component was collected by filtration
8. 8
   Waschenwashed with 12.0 liters of water
9. 9
   Sonstige[A sample of the crude pigment was collected at this point for X-ray analysis
10. 10
    workup.ADDITION] After 50.0 g of 50% aqueous sodium hydroxide was added
11. 11
    Temperaturthe alkaline slurry was heated at 90-92° C. for two hours
12. 12
    FiltrationThe solid component was collected by filtration
13. 13
    Waschenwashed with 12.0 liters of water
14. 14
    TemperaturAfter adjustment of the pH to 9.0, the slurry was heated for two hours in an autoclave at 140° C.
15. 15
    Temperaturcooled to room temperature
16. 16
    workup.ADDITIONAfter adjustment of the pH to 4.5, the slurry was treated with an emulsion of 2.0 g of an anionic surfactant, 25 g of a petroleum distillate, and 40 g of water
17. 17
    workup.STIRRINGstirred for three hours at 45° C
18. 18
    FiltrationThe solid component was collected by filtration
19. 19
    Waschenwashed with 6.0 liters of water
20. 20
    SonstigeThe presscake was dried overnight in an oven at 60° C.

Vorschrift

To 200.0 g of polyphosphoric acid (118%) was added in portions with stirring at 80° C. 50.0 g (133 mmol) of 2,5-bis(p-toluidino)terephthalic acid. The stirred mixture was irradiated in the microwave oven for 2.0 minutes, during which time the temperature rose to 230° C. The reaction mixture was cooled to 150° C. and drowned in 400 g of methanol with vigorous stirring. The resultant methanol suspension was heated at reflux for one hour, cooled to 60° C., added to 800 g of water, and heated at 60° C. for 30 minutes. The solid component was collected by filtration, washed with 12.0 liters of water, and reslurried with water. [A sample of the crude pigment was collected at this point for X-ray analysis.] After 50.0 g of 50% aqueous sodium hydroxide was added, the alkaline slurry was heated at 90-92° C. for two hours. The solid component was collected by filtration and washed with 12.0 liters of water. The resultant presscake (280 g total, with a pigment content of 40.0 g) was reslurried with water. After adjustment of the pH to 9.0, the slurry was heated for two hours in an autoclave at 140° C., then cooled to room temperature. After adjustment of the pH to 4.5, the slurry was treated with an emulsion of 2.0 g of an anionic surfactant, 25 g of a petroleum distillate, and 40 g of water and stirred for three hours at 45° C. The solid component was collected by filtration and washed with 6.0 liters of water. The presscake was dried overnight in an oven at 60° C. to give 38.0 g of pigmentary quality 2,9-dimethylquinacridone. X-ray diffraction patterns of both the dried acid crude (collected as described above) and the finished pigment were similar to the diffraction pattern of a commercially available 2,9-dimethylquinacridone pigment (i.e., QUINDO Magenta RV-6832 from Bayer Corporation) prepared by a conventional heating method.

Quelle